Chapter Preview Questions

1
Chapter Preview Questions

• 1. A solution is an example of a
• a. homogeneous colloid.
• b. heterogeneous colloid.
• c. homogeneous mixture.
• d. heterogeneous mixture.

2
Chapter Preview Questions

• 1. A solution is an example of a
• a. homogeneous colloid.
• b. heterogeneous colloid.
• c. homogeneous mixture.
• d. heterogeneous mixture.

3
Chapter Preview Questions

• 2. Magnesium sulfide and aluminum fluoride are
• a. ionic compounds.
• b. molecular compounds.
• c. covalent electrons.
• d. radioactive elements.

4
Chapter Preview Questions

• 2. Magnesium sulfide and aluminum fluoride are
• a. ionic compounds.
• b. molecular compounds.
• c. covalent electrons.
• d. radioactive elements.

5
Chapter Preview Questions

• 3. When dissolved in water, ionic compounds
• a. conduct electricity.
• b. make the water cloudy.
• c. form double and triple bonds.
• d. do not conduct electricity.

6
Chapter Preview Questions

• 3. When dissolved in water, ionic compounds
• a. conduct electricity.
• b. make the water cloudy.
• c. form double and triple bonds.
• d. do not conduct electricity.

7
Chapter Preview Questions

• 4. When dissolved in water, molecular compounds
• a. conduct electricity.
• b. make the water cloudy.
• c. form double and triple bonds.
• d. do not conduct electricity.

8
Chapter Preview Questions

• 4. When dissolved in water, molecular compounds
• a. conduct electricity.
• b. make the water cloudy.
• c. form double and triple bonds.
• d. do not conduct electricity.

9
What are some characteristics of acids and bases?

• Suppose you dissolve a
• teaspoon of salt in a glass of
• water. Is it possible to recover
• the salt from the water?
• Explain.

10
Section 1 Understanding Solutions

• Standard 8.5.d Students know physical processes
  including freezing and boiling, in which a
  material changes form with no chemical reaction.

11
Section 1 Understanding Solutions

• What are the characteristics of a solution?

• A solution has the same properties throughout.
  It contains solute particles (molecules or ions)
  that are too small to see.
• Solutions
• Contain a solvent, which dissolves the other
  substances
• Contain at least 1 solute, which is dissolved by
  the solvent
• Dissolving one substance into another is a
  physical change.
• The substances retain their original properties.

12
Section 1 Understanding Solutions

• What are the characteristics of a colloid?

• A colloid contains larger particles than a
  solution. The particles are still too small to
  be seen easily, but are large enough to scatter a
  light beam.
• Examples
• milk
• fog
• mayonnaise
• whipped cream

13
Section 1 Understanding Solutions

• What are the characteristics of a suspension?

• A suspension does not have the same properties
  throughout. It contains visible particles that
  are larger than the particles in solutions or
  colloids.

14
Particles in a Solution

• When a solution forms, particles of the solvent
  surround and separate the particles of the solute.

15
Effects of Solutes on Solvents

• Solutes lower the freezing point and raise the
  boiling point of a solvent. Solute particles
  make it harder for water molecules to form
  crystals. Water molecules need more energy to
  boil when a solute is present.

Solid (frozen) water
16
Section 1 Quick Quiz

• How would a solute affect the boiling point of
  water?
• The boiling point will be the same at the
  freezing point.
• The water will not boil.
• The water will boil at a lower temperature.
• The water will boil at a higher temperature.
• Answer D The water will boil at a higher
  temperature.

17
Section 1 Quick Quiz

• When a solute is added to a solvent, the freezing
  point of the solution is
• the same as the freezing point of the solute.
• higher than the freezing point of either
  substance alone.
• lower than the freezing point of either substance
  alone.
• the same as the freezing point of the solvent.
• Answer C lower than the freezing point of
  either substance alone.

18
Section 2 Concentration and Solubility

• Standard 8.5.d Students know physical processes
  including freezing and boiling, in which a
  material changes form with no chemical reaction.

19
Concentration

• How is concentration measured?

• To measure concentration, you compare the amount
  of solute to the total amount of solution.
• A concentrated solution has a lot of solute
  dissolved in a certain amount of solvent.
• A dilute solution has only a little solute
  dissolved in a certain amount of solvent.
• Concentration can be measured as the percent of
  solute in solution by volume or mass.

20
Calculating a Concentration

• To calculate the concentration of a solution,
  compare the amount of solute to the amount of
  solution and multiply by 100 percent.
• For example, if a solution contains 10 grams of
  solute dissolved in 100 grams of solution, then
  its concentration can be reported as 10 percent.

21
Calculating a Concentration

• Practice Problem
• A solution contains 12 grams of solute dissolved
  in 36 grams of solution. What is the
  concentration of the solution?

• 33

22
Calculating a Concentration

• Practice Problem
• A solution contains 15 ounces of solute dissolved
  in 60 ounces of solution. What is the
  concentration of the solution?

• 25

23
Calculating a Concentration

• Practice Problem
• A solution contains 40 grams of solute dissolved
  in 200 grams of solution. What is the
  concentration of the solution?

• 20

24
Solubility

• Solubility is a measure of how much solute can
  dissolve in a solvent at a given temperature.
• If you can continue to dissolve more solute, you
  still have an unsaturated solution.
• If no more solute will dissolve, you have a
  saturated solution.

25
Factors Affecting Solubility

• What factors affect the solubility of a substance?

• Factors that affect the solubility of a substance
  include pressure, the type of solvent, and
  temperature.
• An increase in pressure increases the solubility
  of gases.
• Ionic and polar compounds usually dissolve in
  polar solvents like dissolves like
• The solubility of most solids increases as
  temperature increases.
• Gases become less soluble in a liquid when the
  temperature of the liquid goes up.

26
Temperature and Solubility

• The solubility of the compound potassium nitrate
  (KNO3) varies in water at different temperatures.

27
Temperature and Solubility

• Reading Graphs
• At which temperature shown in the graph is KNO3
  least soluble in water?

• KNO3 is least soluble at 0ºC.

28
Temperature and Solubility

• Reading Graphs
• Approximately what mass of KNO3 is needed to
  saturate a water solution at 40ºC?

• Approximately 65 g of KNO3 are needed to saturate
  a water solution at 40ºC.

29
Temperature and Solubility

• Calculating
• About how much more soluble is KNO3 at 40ºC than
  at 20ºC?

• KNO3 is about twice as soluble at 40ºC as it is
  at 20ºC.

30
Temperature and Solubility

• Interpreting Data
• Does solubility increase at the same rate with
  every 20ºC increase in temperature? Explain.

• No the curve shows that solubility increases
  more with each 20ºC increase in temperature.

31
Section 2 Quick Quiz

• When you add so much solute that no more
  dissolves, you have a
• suspension.
• unsaturated solution.
• saturated solution.
• neutralization.
• Answer C saturated solution.

32
Section 2 Quick Quiz

• What happens to the concentration of sugar in
  maple sap as the sap is boiled?
• The concentration of sugar increases.
• The concentration of sugar remains constant.
• The concentration of sugar becomes 0.
• The concentration of sugar decreases.
• Answer A The concentration of the sugar
  increases.

33
Section 2 Quick Quiz

• If two unidentified solids of the same texture
  and color have different solubilities in 100
  grams of water at 20C, you could conclude that
• they are the same substance.
• they are different substances.
• they have different melting points.
• their solubilities will be the same if the water
  temperature is increased.
• Answer B they are different substances

34
Section 2 Quick Quiz

• A measure of how well a solute can dissolve in a
  solvent at a given temperature is that
  substances
• concentration.
• saturation point.
• acidity.
• solubility.
• Answer D - solubility

35
Section 2 Quick Quiz

• What is one way to increase the solubility of
  sugar in water?
• Heat the water.
• Chill the water.
• Increase the amount of sugar.
• Decrease the amount of water.
• Answer A Heat the water

36
Section 2 Quick Quiz

• A beaker contains 120 grams of salt water
  solution. The salt water has 36 grams of salt
  dissolved in it. What is the concentration of
  the solution?
• 36
• 30
• 72
• 24
• Answer B 30

37
Section 3 Describing Acids and Bases

• Standard 8.5.e Students know how to determine
  whether a solution acidic, basic, or neutral.

38
Properties of Acids and Bases

• What are the properties of acids?
• What are the properties of bases?

• An acid tastes sour, reacts with metals and
  carbonates, and turns blue litmus paper red.
• A base tastes bitter, feels slippery, and turns
  red litmus paper blue.

39
Properties of Acids and Bases

• Litmus is an example of an indicator, a compound
  that changes color when in contact with an acid
  or a base.

40
Uses of Acids and Bases

• Acids and bases have many uses around the home
  and in industry.

41
Uses of Acids and Bases

• Acids and bases have many uses around the home
  and in industry.

42
Uses of Acids and Bases

• Acids and bases have many uses around the home
  and in industry.

43
Uses of Acids and Bases

• Acids and bases have many uses around the home
  and in industry.

44
Uses of Acids and Bases

• Acids and bases have many uses around the home
  and in industry.

45
Uses of Acids and Bases

• Acids and bases have many uses around the home
  and in industry.

46
Uses of Acids and Bases

• Acids and bases have many uses around the home
  and in industry.

47
Uses of Acids and Bases

• Acids and bases have many uses around the home
  and in industry.

48
Uses of Acids and Bases

• Acids and bases have many uses around the home
  and in industry.

49
Uses of Acids and Bases

• Acids and bases have many uses around the home
  and in industry.

50
Uses of Acids and Bases

• Acids and bases have many uses around the home
  and in industry.

51
Uses of Acids and Bases

• Acids and bases have many uses around the home
  and in industry.

52
Section 3 Quick Quiz

• Acids are described as corrosive because they
• taste bitter.
• eat away at other materials.
• turn litmus paper blue.
• feel slippery.
• Answer B eat away at other materials

53
Section 3 Quick Quiz

• Many of the uses of bases take advantage of their
  ability to react with
• other bases.
• metals.
• salts.
• acids.
• Answer D - acids

54
Section 3 Quick Quiz

• Which is a likely use for a base?
• making soaps and detergents
• making foods taste sour
• etching metals for printing
• as a vitamin in your food
• Answer A making soaps and detergents

55
Section 4 Acids and Bases in Solution

• Standard 8.5.e Students know how to determine
  whether a solution is acidic, basic, or neutral.

56
Acids and Bases in Solution

• What kinds of ions do acids form in water?
• Hydrogen ion (H)
• What kinds of ions do bases form in water?
• Hydroxide ion (OH-)

• An acid produces hydrogen ions in water.
• An atom of hydrogen that has lost its electron.
• A base produces hydroxide ions in water.
• A negative ion, made of oxygen and hydrogen.

57
Strength of Acids and Bases

• Strong acids and weak acids act differently in
  water. Hydrochloric acid is a strong acid. Acetic
  acid is a weak acid.

58
The pH Scale

• A low pH indicates that the concentration of
  hydrogen ions is big. In contrast, a high pH
  indicates that the concentration of hydrogen ions
  is low.

59
Acid-Base Reactions

• In a neutralization reaction, an acid reacts with
  a base to produce a salt and water.

60
Section 4 Quick Quiz

• The pH scale measures
• the strength of an acid.
• the concentration of hydrogen ions.
• the concentration of an acid.
• the strength of hydrogen ions.
• Answer B the concentration of hydrogen ions

61
Section 4 Quick Quiz

• If you have a solution of a strong acid and a
  solution of a weak acid of equal concentration
  and volume, then the
• weak acid will produce more hydrogen ions.
• strong acid will have a lower pH.
• strong acid will have a higher pH.
• two solutions will have the same pH.
• Answer B strong acid will have a lower pH

62
Section 4 Quick Quiz

• Normal rainfall is slightly acidic, which means
  its pH must be
• between 7 and 9.
• between 2 and 4.
• between 5 and 7.
• less than 2.
• Answer C between 5 and 7

63
Section 4 Quick Quiz

• Acids naturally present in food are safe to eat
  because they usually are
• weak.
• concentrated.
• dilute.
• strong.
• Answer A - weak

64
Section 4 Quick Quiz

• What does a neutralization reaction produce?
• acids
• bases
• water and a salt
• carbonated water
• Answer C water and a salt

65
Section 4 Quick Quiz

• You can find the pH of a substance by using
• plain paper.
• a conductivity tester.
• a thermometer.
• litmus indicator.
• Answer D litmus indicator

66
Section 4 Quick Quiz

• Neutralization is a reaction between a(n)
• acid and a base.
• acid and a metal.
• base and a salt.
• salt and water.
• Answer A acid and a base

67
Section 4 Quick Quiz

• In a water solution, how do acids differ from
  bases?
• Acids turn litmus blue, while bases turn litmus
  red.
• Acids form salts, but bases do not.
• Hydrogen ions (H) remain dissolved, but
  hydroxide ions (OH-) do not.
• Acids form hydrogen ions (H), while bases form
  hydroxide ions (OH-).
• Answer D - Acids form hydrogen ions (H), while
  bases form hydroxide ions (OH-).